食道胃接合部癌の病理学的特徴―組織発生の面からBarrett食道癌と比較して

Comparison of Carcinoma of the Esophagogastric Junctions with Barrett's Esophageal Cancer from the Aspect of Structual Development

要旨　噴門部は噴門腺粘膜が存在する部と定義され，これは胃噴門部と食道噴門部とに分けられ，それぞれの長さは食道胃接合線（EGJ）から上下1cm以内にあった．本来の噴門腺粘膜はBarrett食道でも比較的によく保たれており，それより口側に伸びた食道噴門腺粘膜に腸上皮化生や癌が好発した．癌の中心が食道胃接合部（EGJ）の上下2cm以内にある噴門部癌とBarrett食道癌は粘液形質の点で近似しており，胃型優位がそれぞれ71％，88％にみられた．噴門部癌の定義はEGJの上下1cm以内に発生した癌と定義すべきであろう．腸型への変化は胃型形質低異型度癌の増殖帯で始まっていた．Barrett粘膜（食道）は“扁平上皮で覆われていた食道（表面）が円柱上皮で覆われた部分で，化生腸上皮の有無や円柱上皮粘膜の長さを問わない”と定義することを筆者は提唱したい．

　The cardiac region defined as the region containing cardiac mucosa is divided into two ; the gastric cardiac region and the esophageal cardiac region. Both regions are limited to within 1 cm below and above the esophagogastric junction (EGJ). The native cardiac mucosa is well preserved even in Barrett's esophagus (BE) and BE carcinoma, but the mucosa above the native esophageal cardiac mucosa shows a high incidence of intestinal metaplasia and adenocarcinoma. Cardiac adenocarcinoma defined as carcinoma within 2 cm below and above the EGJ is very similar in mucous phenotypes to BE carcinoma. In our study, gastric type carcinomas were found in 71% and 88%, respectively. Intestinalization of gastric type carcinoma occurred in the proliferative zone of cancer tubules in the mucosa. Cardiac adenocarcinoma should be revised as carcinoma arising within 1 cm below and above the EGJ in normal conditions. Last we propose a definition of Barrett's mucosa (esophagus) as esophagus lined by columnar epithelium (the esophageal cardiac epithelium), regardless of the presence or absence of intestinal metaplasia or length of columnar mucosa.